LogWrapper.java

1
/*2
* Copyright (C) 2012 The Android Open Source Project3
*4
* Licensed under the Apache License, Version 2.0 (the "License");5
* you may not use this file except in compliance with the License.6
* You may obtain a copy of the License at7
*8
* http://www.apache.org/licenses/LICENSE-2.09
*10
* Unless required by applicable law or agreed to in writing, software11
* distributed under the License is distributed on an "AS IS" BASIS,12
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.13
* See the License for the specific language governing permissions and14
* limitations under the License.15
*/16
package com.example.android.common.logger;17
18
import android.util.Log;19
20
/**21
* Helper class which wraps Android's native Log utility in the Logger interface. This way22
* normal DDMS output can be one of the many targets receiving and outputting logs simultaneously.23
*/24
public class LogWrapper implements LogNode {25
26
// For piping: The next node to receive Log data after this one has done its work.27
private LogNode mNext;28
29
/**30
* Returns the next LogNode in the linked list.31
*/32
public LogNode getNext() {33
return mNext;34
}35
36
/**37
* Sets the LogNode data will be sent to..38
*/39
public void setNext(LogNode node) {40
mNext = node;41
}42
43
/**44
* Prints data out to the console using Android's native log mechanism.45
* @param priority Log level of the data being logged. Verbose, Error, etc.46
* @param tag Tag for for the log data. Can be used to organize log statements.47
* @param msg The actual message to be logged. The actual message to be logged.48
* @param tr If an exception was thrown, this can be sent along for the logging facilities49
* to extract and print useful information.50
*/51
@Override52
public void println(int priority, String tag, String msg, Throwable tr) {53
// There actually are log methods that don't take a msg parameter. For now,54
// if that's the case, just convert null to the empty string and move on.55
String useMsg = msg;56
if (useMsg == null) {57
useMsg = "";58
}59
60
// If an exeption was provided, convert that exception to a usable string and attach61
// it to the end of the msg method.62
if (tr != null) {63
msg += "\n" + Log.getStackTraceString(tr);64
}65
66
// This is functionally identical to Log.x(tag, useMsg);67
// For instance, if priority were Log.VERBOSE, this would be the same as Log.v(tag, useMsg)68
Log.println(priority, tag, useMsg);69
70
// If this isn't the last node in the chain, move things along.71
if (mNext != null) {72
mNext.println(priority, tag, msg, tr);73
}74
}75
}